1. Field of the Invention
The invention herein resides in the field of devices for injecting fluids into a tree and more particularly relates to a hand-held device for injecting an agent into a tree with continuous pressure sensing technology and an onboard central processing unit (CPU) for controlling the device and a method for identifying the state of health of the tree.
2. History of the Prior Art
Tree injection devices typically are used to inject various agents, such as growth retardants or regulators, fertilizers, fungicides, insecticides, herbicides, pesticides and the like into the trunk of a tree. Ideally the injection is into the xylem cells of the outer grown rings of the tree. Most tree injection devices are manually operated. External environmental parameters and the specific characteristics of each individual tree to be injected are rarely evaluated or considered, thereby increasing the risk of damaging the vascular tissues of the plant by, for example, excessive injection pressure.
Tree injection devices often operate under constant pressures and typically are available in two styles: low pressure tree injection devices that operate at a constant pressure of 10 psi or less and high pressure tree injection devices that operate at a constant pressure of about 200 psi or greater. Such constant pressure injection devices present several problems. Low pressure tree injection devices can take up to four hours or more to inject a single dosage into a tree trunk. High pressure systems rapidly (i.e., almost instantaneously) inject the dosage into the trunk of a tree, often resulting in vascular tissue damage that may impede the distribution of the dosage through the xylem cells of the tree. Furthermore, constant pressure tree injection devices do not take into account the fluctuations in resistance encountered when injecting a fluid into a tree.
There is still a need in the art for a tree injection device in which the injection pressure is continually monitored, measured and modified to adapt to back pressure fluctuations. The present invention is directed to these, as well as other, important ends.